Your password unlocks your files—not us.

When you turn on password protection, your browser encrypts the files before they leave your device. Our server stores and sends the scrambled versions. It does not get the password or the key needed to unlock them, so we cannot view or recover those files.

What happens, step by step?

1. You choose a password and select your files.
2. Your browser turns the password into an encryption key and scrambles each file on your device.
3. The files and their details—including file names, notes, and titles—are encrypted before upload.
4. You send the transfer link and password to your recipient separately.
5. The recipient enters the password. Their browser downloads and unlocks the files on their device.

We use standard browser cryptography: AES-256-GCM to encrypt and authenticate files, and PBKDF2-SHA-256 to derive a key from the password. A fresh random value is used for each file. You do not need to understand those names to use the feature: think of the password as the only key to a lock that is fitted before upload.

If the password is lost

There is no password reset, back door, or support override. If you or your recipient lose the password, nobody—including us—can unlock the transfer. The sender will need to upload the files again with a new password.

Choose a strong password

Use a long, unique passphrase and share it through a different channel from the link. Anyone who gets both the link and password can download the files. A weak password may be guessed, so avoid names, short words, and passwords you use elsewhere.

What this does not protect against

• Someone who can use an unlocked sender’s or recipient’s device, or who already knows the password.
• A compromised browser or device, or malicious software running on it.
• A future malicious change to the website code. The website has to deliver the encryption code to your browser; a compromised site could deliver code that tries to capture a password. This protection is designed to keep us from reading files stored on the server during normal operation, not to make that possibility impossible.
• Metadata the service needs to operate, such as your IP address for the secure-transfer usage limit, transfer timing, expiry, and encrypted file sizes. For the limit, we store a keyed hash of your IP—not the plain address—in the usage table, and remove it after 30 days. People sharing a public IP may share the same allowance. File names, notes, and titles in protected transfers are encrypted.

Choose Files for any file type. Files are not scanned for malware, so only open downloads you trust. Choose Images for image galleries and previews. Password-protected transfers never show previews.